With the heater on it only blows cold....until I start moving, then it blows hot. Why?
2006-12-04 03:28:05 · 12 answers · asked by Anonymous in Cars & Transportation ➔ Maintenance & Repairs
check your coolant level
2006-12-04 03:30:10 · answer #1 · answered by me here, where are you? 3 · 2⤊ 1⤋
Yes it could be many things. The coolant level could be low, the heater control valve could also be an issue (if your vehicle even has one, not all do! We don't even know what car this is, be careful with your answers.) Also as far as your vaccum leak is concerned. Your HVAC system may not rely on vaccum. If it does, under acceleration is when you have a drop in vaccum not at idle. You will have the most idle under engine braking conditions and the least under hard accelerations. Idle would fall in the middle. At idle your engine should be pulling steady vaccum of about 15lbs or so under normal healthy conditions. So throw that answer out it is no good..
In my personal opinion, based on experience, I would urge you to first look at your coolant level and from there look into replacing the thermostat. It is not expensive and In the past about 12 years I have seen this be the cause of this condition a good 90% of the time at least.
Hope this gives you some guidance.
2006-12-04 04:07:43 · answer #2 · answered by Clint M 3 · 1⤊ 0⤋
It kinda sounds like you have a weak water pump, or that your heater core is somewhat clogged up. When the engine is idling, the water pump isn't moving as fast, and thus not pumping as hard. When you are sitting there and there is cool air coming out, where is your temp gauge? If it isn't cooling down, it is probably that your water pump isn't able to pump the coolant through your heater core. The best thing to do would be to have your coolant system flushed out.
It couldn't be your vacuum lines, since at idle the engine has the highest vacuum level. If anything, the car would get colder when you were driving.
2006-12-04 04:09:57 · answer #3 · answered by sethle99 5 · 0⤊ 0⤋
It is because of low coolant level. When the car is moving, the water pump is getting water to send to the heater core. When you are stopped, the level is lower. It usually means you have a small leak. You can try the stuff you add to the radiator if you have an older car. I wouldn't put it in a newer car. It will work on small leaks and last quite a while.
2006-12-04 03:55:41 · answer #4 · answered by lincolnbuck 3 · 0⤊ 0⤋
My bet is on the coolant level too low but you did not say what kind of car so....I did have the vaccuum heater valve box on my VW Golf do that because it was defective. Being a 1989 "classic", I decided to replace the valve with a brass garden hose mender and I have heat when I want it now.
2006-12-04 03:59:23 · answer #5 · answered by hfsi@flash.net 2 · 0⤊ 0⤋
you got a vacuum leak on your heater if you will look there is two hoses that run from your motor back to your heater core one will have a black box on it when the valve on the box closes it will make your heater turn off but there is a lever on the bot flip the lever the other way and you will have heat
2006-12-04 03:44:02 · answer #6 · answered by tony 1 · 0⤊ 0⤋
Could be many things from plugged heater core to faulty thermostat. Check out the Magliozzi Borthers from Car Talk on NPR at cartalk.com. They are the best!
2006-12-04 03:30:57 · answer #7 · answered by Tom 2 · 0⤊ 0⤋
You might want to chech the heater core, or the controls that open the vavles to the heater hoses that feed hot water to the heater core.
2006-12-04 03:33:35 · answer #8 · answered by dewhatulike 5 · 0⤊ 0⤋
Car heaters are the engine heat & when the vehicle is moving it is pushed back into the passenger compartment. When stopped the vent fans end up cirulating the outer cooler air.
2006-12-04 03:37:21 · answer #9 · answered by kate 7 · 0⤊ 1⤋
Sounds like a vacuum leak. When your up and running, vacuum would be high and the heater control valve will open. When your at idle, vacuum is dropping and the valve is closing, cutting off the water flow.
2006-12-04 03:37:15 · answer #10 · answered by luckyaz128 6 · 0⤊ 1⤋
Probably cracked vacuum hoses under the dash. Or maybe just loose. Simple and easy to fix. Take to a radiator shop.
2006-12-04 03:30:28 · answer #11 · answered by Anonymous · 0⤊ 0⤋